Published online by Cambridge University Press: 20 November 2018
Let   $a$  be a natural number greater than 1. Let
 $a$  be a natural number greater than 1. Let   ${{f}_{a}}\left( n \right)$  be the order of
 ${{f}_{a}}\left( n \right)$  be the order of   $a\,\bmod \,n$ . Denote by
 $a\,\bmod \,n$ . Denote by   $\omega \left( n \right)$  the number of distinct prime factors of
 $\omega \left( n \right)$  the number of distinct prime factors of   $n$ . Assuming a weak form of the generalised Riemann hypothesis, we prove the following conjecture of Erdös and Pomerance:
 $n$ . Assuming a weak form of the generalised Riemann hypothesis, we prove the following conjecture of Erdös and Pomerance:
 The number of   $n\,\le \,x$  coprime to a satisfying
$n\,\le \,x$  coprime to a satisfying
  $$\alpha \le \frac{\omega \left( {{f}_{a}}\left( n \right) \right)-{{\left( \log \,\log \,n \right)}^{2}}/2}{{{\left( \log \,\log \,n \right)}^{3/2}}/\sqrt{3}}\le \beta $$
 $$\alpha \le \frac{\omega \left( {{f}_{a}}\left( n \right) \right)-{{\left( \log \,\log \,n \right)}^{2}}/2}{{{\left( \log \,\log \,n \right)}^{3/2}}/\sqrt{3}}\le \beta $$
is asymptotic to   $\left( \frac{1}{\sqrt{2\pi }}\int_{\alpha }^{\beta }{{{e}^{-{{t}^{2}}/2}}}dt \right)\frac{x\phi \left( a \right)}{a}$ as
 $\left( \frac{1}{\sqrt{2\pi }}\int_{\alpha }^{\beta }{{{e}^{-{{t}^{2}}/2}}}dt \right)\frac{x\phi \left( a \right)}{a}$ as   $x$  tends to infinity.
 $x$  tends to infinity.